It is well known that coordination anionic polymerization using catalyst systems represented by a Ziegler-Natta catalyst allows for homopolymerization of olefins and dienes. However, it was difficult to provide efficient copolymerization of olefins and dienes using such catalyst systems. For example, while JP 2006-503141 A (PTL 1) and JP 2-061961 A (PTL 2) refer to copolymerization of ethylenes and dienes, there were many problems associated with the use of a special organic metal complex as a catalytic component, limited structures of the obtained polymer, low catalytic activity, low molecular weight of the generated polymer, and so on.